N is an excellent freeware platform game. The plot is that you are a ninja (hence the name N). You love gold, like all ninjas, and you insist on breaking into areas to get the gold. Your enemies are both physics (more on this later) and well-meaning but occasionly homicidal robots.

The robots you face range from stupid ones, who only patrol a certain area and never deviate, to chaingun-armed death machines. What makes this game even more difficult is that if you take a single hit from anything, or fall from too great a height, you will die straight away. With no way to defend yourself other than escaping them, death is very frequent and there is no saving mid-episode.

The maps in N are small but sweet and most of the later ones make you travel a reasonably long way in a very hostile environment. At first glance, the maps look deceptively simple. It's only when you realise that the patrol routes of most of the robots lead into where the developers know the player will try to get to that the whole thing becomes so very, very difficult.

One problem with the game is that the maps definitely vary in difficulty all the way through the game. There are 300 levels in total, and difficulty can massively change between missions in the same episode. I remember the first time I played and how I could get really far into the missions beginning at Episode 20 (the game allows start points from all of the increments of 10 up to 50) but I became totally stuck on the first mission of the fifth episode. It may have just been me, but I found it difficult to do some things and easy to do others.

The missions themselves can be retried as many times as you like, but unless you play on 'Practice' mode you do get a limited amount of time per episode. The time carries over from missions earlier in the episode and can be increased if you are very good and get a lot of gold. You actually finish missions by unlocking the exit door with a key and running out of it. This is made a lot harder by some devilish traps, like trapdoors that close up the exit, making you restart the mission (this happens more than once), but they are in locations which you normally get to by looking for an easy way out or a lot of gold so that you feel as if they are all your own fault.

One of the main attractions of this game is the incredible physics engine that runs it. Astonishingly, they have created believable gravity in Macromedia Flash player and the player can also exploit the acrobatic abilities of N to get where they want to be. There are some minor problems with this, the only real one being due to your inablility to stand forever on a rounded platform (it will all make sense once you play it), but other than this, all is well.

Another attraction is that if you get really good, you can enter your own times in Time Trial mode into a world leaderboard, making it feel as if you have achieved something from all of your hard work, which is always nice, regardless of how good your time is.

N also comes with an editor that is very useful, although not too easy to use by the casual gamer.

Overall, a brilliant game that definitely deserves your download time, I give it 4.2 out of five, due to the occasionally ludicrous difficulty.